/*
 * Copyright 1999-2012 Alibaba Group.
 *  
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing pehttpssions and
 * limitations under the License.
 */
package com.alibaba.dubbo.rpc.protocol.http;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.SocketTimeoutException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.remoting.RemoteAccessException;
import org.springframework.remoting.httpinvoker.HttpComponentsHttpInvokerRequestExecutor;
import org.springframework.remoting.httpinvoker.HttpInvokerProxyFactoryBean;
import org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter;
import org.springframework.remoting.httpinvoker.SimpleHttpInvokerRequestExecutor;

import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.URL;
import com.alibaba.dubbo.remoting.http.HttpBinder;
import com.alibaba.dubbo.remoting.http.HttpHandler;
import com.alibaba.dubbo.remoting.http.HttpServer;
import com.alibaba.dubbo.rpc.RpcContext;
import com.alibaba.dubbo.rpc.RpcException;
import com.alibaba.dubbo.rpc.protocol.AbstractProxyProtocol;

/**
 * HttpProtocol
 * 
 * @author william.liangf
 */
public class HttpProtocol extends AbstractProxyProtocol {

	public static final int DEFAULT_PORT = 80;

	private final Map<String, HttpServer> serverMap = new ConcurrentHashMap<String, HttpServer>();

	private final Map<String, HttpInvokerServiceExporter> skeletonMap = new ConcurrentHashMap<String, HttpInvokerServiceExporter>();

	private HttpBinder httpBinder;

	public HttpProtocol() {
		super(RemoteAccessException.class);
	}

	public void setHttpBinder(HttpBinder httpBinder) {
		this.httpBinder = httpBinder;
	}

	public int getDefaultPort() {
		return DEFAULT_PORT;
	}

	private class InternalHandler implements HttpHandler {

		public void handle(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
			String uri = request.getRequestURI();
			HttpInvokerServiceExporter skeleton = skeletonMap.get(uri);
			if (!request.getMethod().equalsIgnoreCase("POST")) {
				response.setStatus(500);
			} else {
				RpcContext.getContext().setRemoteAddress(request.getRemoteAddr(), request.getRemotePort());
				try {
					skeleton.handleRequest(request, response);
				} catch (Throwable e) {
					throw new ServletException(e);
				}
			}
		}

	}

	protected <T> Runnable doExport(final T impl, Class<T> type, URL url) throws RpcException {
		String addr = url.getIp() + ":" + url.getPort();
		HttpServer server = serverMap.get(addr);
		if (server == null) {
			server = httpBinder.bind(url, new InternalHandler());
			serverMap.put(addr, server);
		}
		final HttpInvokerServiceExporter httpServiceExporter = new HttpInvokerServiceExporter();
		httpServiceExporter.setServiceInterface(type);
		httpServiceExporter.setService(impl);
		try {
			httpServiceExporter.afterPropertiesSet();
		} catch (Exception e) {
			throw new RpcException(e.getMessage(), e);
		}
		final String path = url.getAbsolutePath();
		skeletonMap.put(path, httpServiceExporter);
		return new Runnable() {
			public void run() {
				skeletonMap.remove(path);
			}
		};
	}

	@SuppressWarnings("unchecked")
	protected <T> T doRefer(final Class<T> serviceType, final URL url) throws RpcException {
		final HttpInvokerProxyFactoryBean httpProxyFactoryBean = new HttpInvokerProxyFactoryBean();
		httpProxyFactoryBean.setServiceUrl(url.toIdentityString());
		httpProxyFactoryBean.setServiceInterface(serviceType);
		String client = url.getParameter(Constants.CLIENT_KEY);
		if (client == null || client.length() == 0 || "simple".equals(client)) {
			SimpleHttpInvokerRequestExecutor httpInvokerRequestExecutor = new SimpleHttpInvokerRequestExecutor() {
				protected void prepareConnection(HttpURLConnection con, int contentLength) throws IOException {
					super.prepareConnection(con, contentLength);
					con.setReadTimeout(url.getParameter(Constants.TIMEOUT_KEY, Constants.DEFAULT_TIMEOUT));
					con.setConnectTimeout(url.getParameter(Constants.CONNECT_TIMEOUT_KEY, Constants.DEFAULT_CONNECT_TIMEOUT));
				}
			};
			httpProxyFactoryBean.setHttpInvokerRequestExecutor(httpInvokerRequestExecutor);
		} else if ("commons".equals(client)) {
			HttpComponentsHttpInvokerRequestExecutor httpInvokerRequestExecutor = new HttpComponentsHttpInvokerRequestExecutor();
			httpInvokerRequestExecutor.setReadTimeout(url.getParameter(Constants.CONNECT_TIMEOUT_KEY, Constants.DEFAULT_CONNECT_TIMEOUT));
			httpProxyFactoryBean.setHttpInvokerRequestExecutor(httpInvokerRequestExecutor);
		} else if (client != null && client.length() > 0) {
			throw new IllegalStateException("Unsupported http protocol client " + client + ", only supported: simple, commons");
		}
		httpProxyFactoryBean.afterPropertiesSet();
		return (T) httpProxyFactoryBean.getObject();
	}

	protected int getErrorCode(Throwable e) {
		if (e instanceof RemoteAccessException) {
			e = e.getCause();
		}
		if (e != null) {
			Class<?> cls = e.getClass();
			// 是根据测试Case发现的问题，对RpcException.setCode进行设置
			if (SocketTimeoutException.class.equals(cls)) {
				return RpcException.TIMEOUT_EXCEPTION;
			} else if (IOException.class.isAssignableFrom(cls)) {
				return RpcException.NETWORK_EXCEPTION;
			} else if (ClassNotFoundException.class.isAssignableFrom(cls)) {
				return RpcException.SERIALIZATION_EXCEPTION;
			}
		}
		return super.getErrorCode(e);
	}

}